Gamma-crotonolactone is commercially and industrially attractive for its potential as an intermediate in the manufacture of 1,4-butanediol and tetrahydrofuran. Gamma-crotonolactone is also useful as an organic intermediate and monomer for various polymerization reactions. Gamma-crotonolactone has been employed in the synthesis of methyl chrysanthemate which is a powerful insecticide, and the synthesis of cerulenin, an antibiotic and staganacin an anti-leukemia agent. Further, substituted crotonolactones are useful as cardiac glycosides and as agricultural chemicals.
A need exists for a commercially acceptable process for the production of gamma-crotonolactone that is direct and versatile in order to broaden its commercial availability.
Various prior art methods exist for the production of lactones, including, for example, the methods described in the following patents: U.S. Pat. Nos. 4,356,310; 4,175,089; 4,069,232 and 3,061,614. Various literature references disclose the catalytic carbonylation of epoxides in alcoholic solutions to form 3-hydroxy esters [e.g., Heck, R. F., J. Am. Chem. Soc., Vol. 85, pp. 1460-1463 (1963)]and carbonylation of an epoxy olefinic compound to form lactones [e.g., Aumann, R., Ring, H., Angew. Chem., Vol. 89, pp. 47-48 (1977)]. German Pat. No. 1,066,572 discloses carbonylation of trimethylene oxide to gamma-butyrolactone.